Genome sequences contain the information needed for the development and function of a given species. Exploring conservation of DNA sequence between species is a tool for identifying critical code that is likely to be important for functions shared between species. Genomic information is deployed by transcription and differential expression may well be important for phenotypic distinctions among closely related species. Comparative transcription has not been extensively explored. [unreadable] [unreadable] We performed DNA microarray profiling of expression in several of the newly sequenced Drosophila species. These expression data provide the only biological evidence for most of the predicted genes in these species. Additionally, we observed strong selection against genes with male-biased expression on the X chromosomes of these species, as well as correlations between sequence divergence and expression divergence.